The automobile is one of the most significant inventions in modern history. Few other inventions have had as much influence over the lives of so many people in so many ways. It has made possible for individuals to reach distant work locations, live in towns and cities, expand their social circles by adding new friends, and even change careers. But the automobile has also facilitated a leisure lifestyle and brought with it changes in shopping, entertainment, restaurants and other services. It has helped to develop cities and suburbs, and has contributed to the destruction of wilderness. It has fueled new laws and regulations on highway safety, driver’s licenses, seatbelts and driving speed limits. And it has also caused harm to the environment through exhaust emissions and the use of land that could have been used for other purposes.
The history of the automobile began in the 1860s and ’70s with the development of the gasoline engine, followed by a proliferation of manufacturers who produced vehicles with this technology. By 1920, the automobile had dominated the streets and byways of the world. Henry Ford revolutionized automotive manufacturing by developing assembly lines to reduce the cost of his Model T runabout until it was affordable for middle-class Americans. This was just the beginning; the automobile would go on to have a profound impact in nearly every aspect of human life.
Automobiles are powered by an internal combustion, piston-type engine fueled most often by gasoline (liquid petroleum gas), although diesel engines — which burn a heavier oil — are used in heavy vehicles such as trucks and buses, and in some passenger cars. Most automobiles are manufactured as a monocoque or unibody design, with front-wheel drive and transversely mounted engines. Some models are designed for high-speed driving, which requires more power and a bigger engine than a car primarily intended for city driving. Some are built for luxury or economy, while others are sporty or family-oriented.
The various factors that affect the design of an automobile are complex and vary depending on the vehicle’s use, but the basic components remain the same: a body, chassis, suspension system, wheels and tires, engine, transmission, cooling and lubrication systems, electrical system, and brakes. The arrangement and choice of these components, however, must be flexible enough to accommodate a variety of uses and driving conditions. Each feature must be carefully balanced to satisfy several different considerations — comfort, handling, acceleration, fuel efficiency, and durability being among them. The result is a great diversity of automobile designs. But for all this variety, a number of general features distinguish the automobile as the most influential of all modern machines.